7 research outputs found

    Internationale Konferenz: Wismut 2000 - Bergbausanierung Tagungsband

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    Main topics of the international conference on mine rehabilitation were: decommissioning of exploited uranium mines, covering of tailings, ground water decontamination, flooding of mines, reshaping of landscapes in abandoned coal mining regions, environmental compliance requirements, treatment of contaminated waters.SIGLEAvailable from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

    Passive Wasserbehandlungsverfahren Tagungsband

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    During and following the remediation of the legacy left by the mining and processing of uranium ores in the Free States of Saxony and Thuringia of the Federal Republic of Germany, contaminated waters are produced which contain toxic elements and radionuclides and which must not be discharged into receiving streams without prior treatment. Such effluents include waters from flooded mines, supernatant and pore water from tailings ponds as well as mine dump seepage. From the point of view of WISMUT GmbH, at a certain level of contaminant loads to be removed, passive procedures based on biological and physico-chemical processes will be a cost-effective alternative to conventional techniques. With the Workshop 'Passive Water Treatment Techniques' on November 13 and 14, 2000 WISMUT GmbH pursued the objective to - keep themselves informed about international developments in the field of alternative water treatment techniques; - become acquainted with results and problems encountered in the operation of facilities based on alternative techniques; - inform about WISMUT's own developments and experience gained from the operation of pilot-scale plants; - present projects within the overall WISMUT remediation program on the development and implementation of passive water treatment techniques by 2005; -hold an exchange of ideas about the information presented with experts from Germany and abroad and with representatives of the regulatory authorities on chances and risks inherent in passive water treatment systems with particular attention being given to long-term aspects. (orig.)SIGLEAvailable from TIB Hannover: F02B714 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

    Entwicklung eines Verarbeitungsverfahrens zur Verwertung U- und Th-haltiger Reststoffe Schlussbericht

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    Studies are performed on c. 100 kg each of excavated oil and building rubble contained in steel drums which were provided as samples by NUKEM GmbH. Prior to these tests, studies had been run using radioactively contaminated excavated soil and building rubble of Wismut provenance. Excavated soil, in particular, was expected to have specific processing properties and requirements differing from uranium one processing owing to the relatively high content of organic compounds in the soil. On completion of these test series, studies were run for the separation of radium and thorium. The results of all studies were taken to develop the technology for industrial-scale testing of waste disposal of excavated soil containing U-235/U_t_o_t_a_l>0.71% in the Seelingstaedt treatment facility of Wismut GmbH. Once this test will have produced positive results, the technology envisaged will be taken as the base of waste disposal of radioactively contaminated residues at Wismut GmbH. (orig./EF)Fuer die Versuche wurden von der NUKEM GmbH ca. 100 kg Erdaushub und Bauschutt in Stahlfaessern zur Verfuegung gestellt. Vor der Verarbeitung der Nukemproben wurden mit radioaktiv kontaminiertem Erdaushub und Bauschutt der Wismut Vorversuche durchgefuehrt. Es war anzunehmen, dass insbesondere Erdaushub, wegen des relativ hohen Gehaltes an organischen Stoffen, aufbereitungstechnische Besonderheiten gegenueber der Aufbereitung von Uraniumerz aufweist. Nach Abschluss dieser Versuchsreihen erfolgten Untersuchungen zur Abtrennung von Radium und Thorium. Mit den Ergebnissen aller Laborversuche wurde die Technologie fuer einen grosstechnischen Versuch zur Entsorgung von Erdaushub mit U-235/U_g_e_s_.>0,71% im Sanierungsbetrieb Seelingstaedt der Wismut GmbH ausgearbeitet. Nach positivem Ablauf des gesamten Versuches kann die vorgeschlagene Technologie die Grundlage fuer eine Entsorgung radioaktiv kontaminierter Reststoffe durch die Wismut GmbH sein. (orig./EF)SIGLEAvailable from TIB Hannover: F94B1776+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

    Kleintechnische Erprobung der Haldensickerwasserreinigung in Schlema Untersuchungsbericht Nr. 92005

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    The concentrations of uranium, arsenic, and radium remain well below the maximum permissible values of < 0.1 mg/l (uranium), < 0.1 mg/l (arsenic) and < 100 mBq/l (radium) due to two separation stages with barium sulfate and GoPur 3000 precipitation and due to iron hydroxide/iron arsenate precipitation. The radioactive arsenates can be separated from the toxic ones by separating the sludge which is analyzed. Processing of radioactive sludges leaves reusable GoPur 3000, sulfuric solutions which contain uranium or solutions which contain carbonate, and radioactive barium sulfate whose radiation intensity of 12 mBq/g is due to the presence of radium. The sludge produced contains adsorbed salts in addition to the dosed chemicals (floated sludges: 40 g/m"3, iron sludges < 20 g/m"3). A solids content < 100 g/m"3 can be selected for both sludge portions. Static-mixer chemicals dosing and technical improvements of the tubular reactor are required for optimization of the pilot plant. Estimation of the cost of waste dump leachates cleaning on a m"3 scale reveals the great share of energy costs in the operating costs. The cost of chemicals amounts to 1 mark/m"3 of the estimated cost of ca. 2.50 marks/m"3. (orig.)Die Grenzwerte der Schadstoffe Uran < 0,1 mg/l, Arsen < 0,1 mg/l, Radium < 100 mBq/l werden durch zwei Trennstufen mit Bariumsulfat- und GoPur"R 3000-Faellung und durch Eisenhydroxid/Eisenarsenatfaellung sicher unterschritten. Eine Trennung der radioaktiven von den toxischen Arsenaten ist in separaten Schlammvolumina moeglich. Eine Aufarbeitung des radioaktiven Schlammes fuehrt zu wiederverwendbarem GoPur"R 3000, uranhaltiger schwefelsaurer oder carbonathaltiger Loesung und radioaktivem Bariumsulfat mit 12 mBq/g auf Radium zurueckgehender Strahlenintensitaet. Der anfallende Schlamm enthaelt neben den dosierten Chemikalien (Flotatschlamm: 40 g/m"3; Eisenschlamm < 20 g/m"3) auch adsorbierte Salze. Der Feststoffanteil beider Schlaemme ist auf < 100 g/m"3 einstellbar. Fuer die Optimierung der Versuchsanlage ist die Chemikaliendosierung und die verfahrenstechnische Ueberarbeitung der Rohrreaktoranlage mit statischen Mischern notwendig. Die Abschaetzung der bei der Haldensickerwasserreinigung im m"3-Massstab entstehenden Kosten zeigt, dass die Energiekosten einen erheblichen Anteil der Betriebskosten ausmachen. Die Chemikalienkosten gehen in den Preis von #approx# 2,50 DM/m"3 mit 1 DM/m"3 ein. (orig.)Available from TIB Hannover: F94B973+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

    Heavy Metal Tolerance of Fe(III)-Reducing Microbial Communities in Contaminated Creek Bank Soils▿†

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    Fe(III)-reducing soil enrichment cultures can tolerate 100 μM Cu and Cd, 150 μM Co, 600 μM Ni, and 2,500 μM Zn. Metal-tolerant cultures were dominated by Geobacter-related Deltaproteobacteria and Gram-positive Firmicutes spp. (Clostridia and Sedimentibacter). A Cd- and Cu-tolerant Fe(III)-reducing coculture of Desulfosporosinus and Desulfitobacterium indicated the importance of the Firmicutes for Fe(III) reduction in the presence of metals

    Uranium from Africa – An overview on past and current mining activities: Re-appraising associated risks and chances in a global context

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